An isolated DC-to-DC converter comprises a converter section configured to
receive an input voltage and produce an isolated output voltage and a
controller section configured to control the operation of the converter
section to maintain the output voltage at a predetermined value by, at
least in part, turning switches on and off at a certain duty cycle at a
set switching frequency. The controller section comprises an isolation
transformer providing primary and secondary side isolation and an error
amplifier having an output coupled to the isolation transformer, the
error amplifier providing an error signal that is representative of the
difference between an output voltage and a desired output voltage. The
converter further comprises an isolation driver coupled to an isolation
driver switch, the isolation driver operable to turn on and off the
isolation driver switch at the same frequency as the converter section,
the switching of the isolation driver switch resulting in the error
signal becoming an amplitude modulated error signal that is transferred
across the isolation transformer.